1. Field of the Invention
This invention relates to a method for measuring temperature distribution on the surface of a sample and a system for the same. Moreover, this invention relates to a method for easily measuring temperature distribution on the surface of a sample consisting of a plurality of coexisting materials having different radiation coefficients of infrared ray at the specified temperature and a system for the same.
2. Description of the Prior Art
Conventionally, for the measurement of surface temperature of a material, an amount of the radiated ray, such as infrared ray, is measured in order to know an intensity of heat radiated from the surface of said material, and it is calibrated by temperature. Since an amount of radiated ray at the specified temperature is different according to a material, temperature calibration mentioned above is required. Therefore, in order to calibrate the amount of radiated ray to a temperature, it is necessary to know the radiation coefficient of the radiated ray of the sample to be measured.
In other words, first of all, it is necessary to previously search an intensity of radiated heat at each temperature of a material having the radiation coefficient of 1.0, for example, a black radiation body. Then, an intensity of radiated heat of the sample to be measured is converted to a value of a sample having the radiation coefficient of 1.0. For example, a radiation coefficient of a sample is considered as .alpha., and the above conversion can be done on the basis of the equation, radiated heat intensity x l/.alpha.. Then, an actual temperature of the sample can be determined from the relation between a radiated heat intensity and each temperature of the material having a radiation coefficient of 1.0 searched previously.
The method mentioned above easily provides a surface temperature distribution of a sample consisting of a homogeneous material having the previously known radiation coefficient.
However, in the case of a sample consisting of various coexisting materials such as the surface of an integrated circuit, if the radiation coefficient of each region at the surface of said sample is unknown, a surface temperature distribution cannot be obtained. This is a serious disadvantage of the conventional method. Moreover, it is very difficult to know the radiation co-efficient of each region on the surface of the abovementioned sample.